bug修复

src/main/java/com/project/classicpaper/application/ClassicCategoryApplicationService.java

@@ -11,5 +11,7 @@ public interface ClassicCategoryApplicationService {
 
     Result<ClassicCategoryDTO> save(ClassicCategoryDTO dto) throws Exception;
 
+    Result<ClassicCategoryDTO> rename(Long id, String name) throws Exception;
+
     Result<String> delete(Long id) throws Exception;
 }

src/main/java/com/project/classicpaper/application/impl/ClassicCategoryApplicationServiceImpl.java

@@ -49,7 +49,9 @@ public class ClassicCategoryApplicationServiceImpl implements ClassicCategoryApp
         Map<Long, List<ClassicPaperSetDTO>> paperSetMap = Boolean.TRUE.equals(withPaperSet) ? new HashMap<>() : null;
         for (ClassicPaperSetEntity set : allPaperSets) {
             Long catId = set.getClassicCategoryId();
-            if (catId == null) continue;
+            if (catId == null) {
+                continue;
+            }
             countMap.merge(catId, 1, Integer::sum);
             if (paperSetMap != null) {
                 //按分类ID分组套题组
@@ -163,6 +165,46 @@ public class ClassicCategoryApplicationServiceImpl implements ClassicCategoryApp
         return Result.success(entity.toDTO(ClassicCategoryDTO::new));
     }
 
+    @Override
+    public Result<ClassicCategoryDTO> rename(Long id, String name) throws Exception {
+        // 1. 参数校验
+        if (id == null) {
+            throw new BusinessErrorException("分类ID不能为空");
+        }
+        if (StrUtil.isBlank(name)) {
+            throw new BusinessErrorException("分类名称不能为空");
+        }
+        if (StrUtil.length(name) > 50) {
+            throw new BusinessErrorException("分类名称过长");
+        }
+
+        // 2. 分类存在性校验
+        ClassicCategoryEntity entity = classicCategoryBaseService.getById(id);
+        if (entity == null) {
+            throw new BusinessErrorException("分类不存在");
+        }
+
+        // 3. 名称未变更则直接返回
+        if (StrUtil.equals(entity.getName(), name)) {
+            return Result.success(entity.toDTO(ClassicCategoryDTO::new));
+        }
+
+        // 4. 同父级下重名校验
+        LambdaQueryWrapper<ClassicCategoryEntity> duplicateQuery = new LambdaQueryWrapper<ClassicCategoryEntity>()
+                .eq(ClassicCategoryEntity::getName, name)
+                .eq(ClassicCategoryEntity::getParentId, entity.getParentId())
+                .ne(ClassicCategoryEntity::getId, id);
+        if (classicCategoryBaseService.count(duplicateQuery) > 0) {
+            throw new BusinessErrorException("同级下已存在同名分类");
+        }
+
+        // 5. 只更新 name 字段，避免覆盖其他字段
+        entity.setName(name);
+        classicCategoryBaseService.updateById(entity);
+
+        return Result.success(entity.toDTO(ClassicCategoryDTO::new));
+    }
+
     @Override
     public Result<String> delete(Long id) throws Exception {
         ClassicCategoryEntity category = classicCategoryBaseService.getById(id);

src/main/java/com/project/classicpaper/controller/ClassicCategoryController.java

@@ -31,6 +31,11 @@ public class ClassicCategoryController {
         return classicCategoryApplicationService.save(dto);
     }
 
+    @PostMapping("/rename")
+    public Result<ClassicCategoryDTO> rename(Long id, String name) throws Exception {
+        return classicCategoryApplicationService.rename(id, name);
+    }
+
     @PostMapping("/delete")
     public Result<String> delete(Long id) throws Exception {
         return classicCategoryApplicationService.delete(id);